Yield and Quality in Main and Ratoon Crops of Grain Sorghum Under Different Nitrogen Rates and Planting Densities

Ratooning is the cultivation practice of two harvests in one cropping season by producing a second crop from the original stubble, which could provide higher resource use efficiency and economic benefit compared with direct sown crops. Nitrogen (N) fertilizer and planting density (D) play a vital role in sorghum (Sorghum bicolor L.) production; however, limited information is available on the effects on yield and quality of the sorghum-ratoon system. To address this question, field experiments were conducted with three N treatments (120 kg N ha–1, N1; 180 kg N ha–1, N2; and 255 kg N ha–1, N3) and three D treatments (82,500 plant ha–1, D1; 105,000 plant ha–1, D2; and 127,500 plant ha–1, D3). The yield of the main crop was significantly higher than that of the ratoon crop. Increasing N could increase the yield and yield attributes of both main and ratoon crops, and the effect on the ratoon crop was greater than the main crop. With increasing D, the grain yield of both main and ratoon crops increased, though 1,000-grain weight and grain weight per ear decreased. The sorghum grain of the ratoon crop contained higher starch, protein, and tannin contents but lower fat content, indicating a better quality for liquor production. The quality traits were significantly affected by N and D, but the differences between treatments were smaller than that between the main and ratoon crop. Our results indicated that increasing the yield of ratoon crops could obtain a high yield and quality of the sorghum-ratoon system. It was recommended that 120 kg N ha–1 with 127,500 plant ha–1 for the main crop and a small amount of N be top-dressed in three new buds left on stubble in each hill for the ratoon crop.

The Process of Separating Buckwheat and Wheat Grain in a Pneumatic Cone Separator in the Context of Sustainable Agriculture

In machines and devices used for separating and cleaning seed mixtures, the components of such mixtures can be separated in a stream of air. The efficiency of separation of a two-component (model) mixture containing wheat kernels and buckwheat nutlets was investigated. The main crop seeds and other crop seeds imitating impurities accounted for 80% and 20% (w/w), respectively. The experiment involved a pneumatic cleaning device with an immobile conical surface, designed by the authors, where mixture components are separated in a stream of air. The seed mixture was separated in a separator with the shape of an inverted cone, where the seeds were set into motion by a stream of air. The separation efficiency of the analyzed two-component mixture in the designed separator exceeded 78%. Regression equations describing the separation efficiency index of the entire seed mixture (ε) and the separation efficiency of the main crop seeds (ηp) and seeds imitating impurities (ηz) were derived. The coefficient of determination (R2) for the above regression equations describing the separation efficiency of the mixture components (main crop seeds and seeds imitating impurities) and the separation efficiency index of the entire seed mixture ranged from 0.81 to 0.94. This result indicates that the developed equations were characterized by satisfactory and highly satisfactory fit to empirical data, and that they can be applied to accurately predict the quality of the seed separation process in the cleaning device designed by the authors. The developed equations can be effectively used to model and automatically control separation processes in the proposed separator.

Strategic level of agrocenoses state management

The aim of the work is to develop a theoretical basis for solving the problem of managing the state of agrocenoses, which contain crops of the main crop and weeds. The solution to this problem is aimed at eliminating the limitations of the existing paradigm of separate management of the state of crops and weeds. The proposed theory and methodology is based on taking into account the relationship between the state of crops and weeds, and their overall effect on the content of nutrients in the soil. For this, a system of mathematical models has been proposed, in which these relationships and yield losses are taken into account when the parameters of the chemical state of the soil deviate from the optimal values for crop rotation and from the effect of herbicide treatments on crop sowing. The result of solving the problem is the optimal strategies for the introduction of mineral fertilizers, ameliorants and herbicides by years of crop rotation. These strategies ensure that yield losses are minimized for all crops, rotation and agrochemical consumption. The results obtained are new, since such tools are currently lacking.

Impact of the Legume Catch Crop Serradella on Subsequent Growth and P Mobilization under Barley in Different Fertilization Treatments

Legume catch crops can enhance soil fertility and promote the N and P supply of the subsequent main crop, especially with low mineral fertilizer use. However, the specific impact of catch crops on arbuscular mycorrhiza formation of the following main crop is unknown. Therefore, the impact of serradella (Ornithopus sativus) vs. bare fallow was tested on mycorrhiza formation, potential soil enzyme activities and plant-available P under subsequently grown barley (Hordeum vulgare) and different fertilization treatments (P-unfertilized—P0; triple superphosphate—TSP; compost—COM; combined—COM + TSP) in a long-term field experiment in northeastern Germany. Catch cropping significantly increased mycorrhiza formation of barley up to 14% compared to bare fallow. The impact of serradella on mycorrhiza formation exceeded that of the fertilization treatment. Serradella led to increased phosphodiesterase activities and decreased ß-glucosidase activities in soil. Plant availability of P was not significantly affected by serradella. These findings provide initial evidence that even serradella as a non-host crop of mycorrhizal fungi can promote the mycorrhiza formation of the subsequent crop and P mobilization in soil. We conclude that the prolonged vegetation cover of arable soils by the use of catch crops can promote P mobilization and transfer from P pools to the following main crops.

Productive capacity of the maize for silage crop grown in disturbed irrigation regime

An experiment was conducted with maize for silage as a main irrigation culture in the experimental field of the Agricultural Institute - Stara Zagora. The following variations have been tested: variation 1 - no irrigation (sentinel); variation 2 - optimal irrigation, 80%-85% of FC (100% irrigation); variation 3 - Irrigation as variation 2 but with first irrigation cancelled; variation 4 - irrigation as variation 2 but with second irrigation cancelled; variation 5 - irrigation as variation 2, but with third irrigation cancelled. On the basis of a chemical analysis of the sudangrass forage for the raw protein content, FUM, FUG and PDI were defined. It was found that the highest yield of raw maize protein grown as the main crop was obtained from the optimal irrigation variation, both in the non-fertilized and the fertilized variation, respectively with 1023.5 kg / ha and 1303.5 kg / ha. The optimal water supply of maize provides the highest energy efficiency of the forage expressed in FUM -15022.8 kg / ha, FUG -15584.4 kg / da, PDI - 1060 kg / ha for non fertilized variations and FUM -16873.5 kg / ha, FUG -17516.3 kg / ha, PDI-1219 kg / ha with fertilizer applied.

Soil nitrogen and water management by winter-killed catch crops

Improving N cycling in agroecosystems is one of the key challenges in reducing the environmental footprint of agriculture. Further, uncertainty in precipitation makes crop water management relevant in regions where it has not been necessary thus far. Here, we focus on the potential of winter-killed catch crops to reduce N leaching losses from N mineralization over the winter and soil water management. We compared four single catch crops (white mustard, phacelia, Egyptian clover and bristle oat) and a fallow treatment with two catch crop mixtures with 4 and 12 plant species (Mix4 and Mix12). High-resolution soil mineral N (Nmin) monitoring in combination with modelling of spatiotemporal dynamics served to assess N cycling under winter-killed catch crops, while soil water was continuously monitored in the rooting zone. Catch crops depleted the residual Nmin pools by between 40 and 72 % compared to the fallow. The amount of residual N uptake was lowest for clover and not significantly different among the other catch crops. Catch crops that produce high N litter materials, such as clover and mustard leaves, showed an early N mineralization flush immediately after their termination and the highest leaching losses from litter mineralization over the winter. Except for clover, all catch crops showed Nmin values between 18 and 92 % higher on the sowing date of the following maize crop. However, only Mix12 was statistically significant. Catch crops depleted the soil water storage in the rooting zone during their growth in autumn and early winter, but preserved water later on when their residues cover the ground. The shallow incorporation of catch crop residues increased water storage capacity during the cropping season of the main crop even under drought conditions. Hence, catch cropping is not just a simple plant cover during the winter but improved the growth conditions for the following crop at decreased N losses. Mixtures have been shown to compensate for the weaknesses of individual catch crop species in terms of nutrient capture, mineralization and transfer to the following main crop as well as for soil water management. Detailed knowledge about plant performance during growth and litter mineralization patterns is necessary to make optimal use of their full potential.

Comparison of Ruminal Degradability, Indigestible Neutral Detergent Fiber, and Total-Tract Digestibility of Three Main Crop Straws with Alfalfa Hay and Corn Silage

Three main crop straws including corn straw (Zea mays, CS), rice straw (Oryza sativa, RS), and wheat straw (Triticum aestivum, WS), and two forages including alfalfa hay (Medicago sativa, AH) and corn silage (Zea mays, CSil) were analyzed in order to compare their ruminal degradability, indigestible neutral detergent fiber (iNDF), intestinal digestibility (ID), and their total-tract digestibility (TTD) of crude protein (CP), neutral detergent fiber (NDF), and acid detergent fiber (ADF) using both an in situ nylon bag technique and a mobile nylon bag technique. The forage samples were incubated in the rumen for 6, 12, 16, 24, 36, 48, 72, and 288 h, respectively, to determine their ruminal degradability. Prior to intestinal incubation, forage samples were incubated in the rumen for 12 h and 24 h to determine the ruminal degradable content of CP, NDF, and ADF, respectively, and for 288 h to determine their iNDF288 content. Residues from the ruminal undegradable fractions (12 h for CP, 24 h for NDF and ADF) were subsequently inserted into the duodenum through a cannula to determine their intestinal digestible content. Here, the TTD of CP, NDF, and ADF were determined as the ruminal degradable content + intestinal digestible content. The results showed that AH had the highest iNDF2.4 (calculated as acid detergent lignin content × 2.4) and iNDF288 values (379.42 and 473.40 g/kg of NDF), while CS and CSil had the lowest iNDF2.4 values (177.44 and 179.43 g/kg of NDF). The ruminal degradability of CP, NDF, and ADF for CS, RS, and WS were lower than those of AH and Csil during the first 48 h of incubation. The potential degradation fraction of CP, NDF, and ADF for CSil was the highest; CS, RS, and WS were intermediate; and AH was the lowest (p < 0.05). CS, RS, and WS had a lower intestinal digestibility with respect to their rumen undegradable content of NDF (p < 0.05), and lower TTD of CP, NDF, and ADF (p < 0.05) compared to AH and CSil. General regression equations with satisfactory accuracy (R2 ≥ 0.828) were derived to predict iNDF288 and TTD based on their chemical compositions and the ruminal degradation kinetics of different forages. Incorporating this information into rations could improve our ability to optimize main crop straws utilization and milk production.

A Framework for the Heterogeneity and Ecosystem Services of Farmland Landscapes: An Integrative Review

It is essential for the sustainable development of farmland landscapes to balance ecosystem service trade-offs and improve resource use efficiency during crop production. Thus, an integrative and concept-centric qualitative approach was applied by combining the patch–corridor–matrix model of landscape ecology and the crop layout theory of farming systems into a theoretical framework. The thesis concludes that a farmland landscape comprises three compositions: the crop (the main crop and the service crop), the non-crop, and the non-vegetation, leading to heterogeneous composition and configuration. The main crop, typically displayed as large patches with a high distribution ratio, provides most of the provisioning services, while the service crop performs many regulation services. The non-crop and non-vegetation compositions often appear as strips that can connect different patches as corridors and support the provisioning services of crops. Non-crop compositions mainly focus on support and regulation services, while non-vegetation compositions support farming operations. Further research is needed in several respects, including the ecological impact and ecosystem service trade-offs of the composition and configuration heterogeneity, and strategies for the adoption of cropping systems and agronomic measures at the landscape scale, which are essential to the evaluation, improvement, and redesign of farmland landscapes.

Cleaning of vegetable seeds on a pneumatic sorting table

Семенной ворох с поля никогда не бывает чистым. В процессе уборки семян в семенной ворох попадают различные примеси – семена сорняков, различные обломки частей растений, минеральные частицы: комочки земли, камешки и др. Очистка семенного вороха до регламентированных показателей, предусмотренных в нормативном документе, – основная задача послеуборочной доработки семян. Примеси, которые отличаются размером от семян основной культуры, легко удаляются на ветрорешетных машинах. Полностью удалить все примеси на ветрорешетных машинах невозможно. Поэтому существует необходимость во вторичной, более качественной очистке семенного вороха. Пневмосортировальные столы способны разделить семенной ворох по плотности семян. В результате дополнительной вторичной очистки семян можно повысить чистоту семян, которая необходима для безотказной работы современных высевающих аппаратов. Пневмосортировальный стол ПСС-1 имеет ряд настроек, которые меняются оператором в зависимости от культуры. Основные настройки: подача семян, регулировка заслонки вентилятора, изменение продольного и поперечного угла наклона рабочей деки, частота колебания рабочей деки, регулируемые заслонки приемника семян. Все настройки могут быть оперативно изменены оператором технологического процесса очистки. Использование пневмосортировального стола во вторичной очистке семенного вороха возможно на различных овощных культурах. В процессе очистки семян на пневмосортировальном столе из семенного вороха удаляются вместе с легковесными примесями, обломками стебельков, листьев, стручков и прочими, удаляются и легковесные невызревшие семена, что способствует повышению всхожести получаемых после очистки семян. The resulting seed heap from the field is never clean. In the process of harvesting seeds, various impurities are found in the seed pile. As impurities in the seed heap, there may be weed seeds, various fragments of plant parts, mineral particles: lumps of earth, pebbles and others. Cleaning the seed pile to the regulated indicators provided for in the regulatory document is the main task of post-harvest seed refinement. Impurities that differ in size from the seeds of the main crop are easily removed by wind-screen machines. It is impossible to completely remove all impurities on windscreen machines. Therefore, there is a need for a secondary, better cleaning of the seed pile. Pneumatic sorting tables are able to divide the seed pile according to the density of seeds. Because of additional secondary cleaning of seeds, it is possible to increase the purity of seeds, which is necessary for the trouble-free operation of modern sowing machines. The PSS-1 pneumatic sorting table has a number of settings that are changed by the operator depending on the culture. Basic settings: seed feeding, fan flap adjustment, changing the longitudinal and transverse angle of inclination of the working deck, the oscillation frequency of the working deck, adjustable shutters of the seed receiver. The operator of the cleaning process can quickly change all settings. The use of a pneumatic sorting table in the secondary cleaning of the seed pile is possible on various vegetable crops. In the process of cleaning seeds on a pneumatic sorting table, fragments of stems, leaves, pods and others are removed from the seed pile together with lightweight impurities, and lightweight unripe seeds are also removed, which helps to increase the germination of seeds obtained after cleaning.

Systematic Investigation of Plant-Parasitic Nematodes Associated with Main Subtropical Crops in Guangxi Province, China

Plant parasitic nematodes (PPNs) are a pathogenic group that causes momentous crop yield loss by retarding plant growth and development through plant parasitization. In this study, the distribution of PPNs based on the main crops in Guangxi Province of China was investigated. A total of 425 samples of soil or roots from sugarcane, rice, maize, and soybean were collected in 68 counties, and a total of 48 order/family/genera of PPNs were identified, of which some genera were found in more than one crop. A total of 31 order/family/genera of PPNs were found in rice, among which Hirschmanniella was the most abundant, accounting for 79.23%, followed by Tylenchorhynchus (34.43%). Forty order/family/genera were observed in maize, of which the dominant genera were Pratylenchus and Tylenchorhynchus at 45.14% and 32.64%, respectively. In addition, 30 order/family/genera of PPNs were detected from sugarcane, and the percentages of Tylenchorhynchus and Helicotylenchus were 70.42% and 39.44%, respectively. The main crop of Eastern ecological regions was rice, with a high frequency of Hirschmanniella. The greatest frequency of Pratylenchus was found in the Western eco-region, which had a large area of maize. In the Northern eco-region, rice and maize were popular, with abundant Hirschmanniella and Helicotylenchus. In the Central eco-region, Pratylenchus was detected on the main crop of sugarcane. Hirschmanniella (72.94%) was dominant in clay, and Tylenchorhynchus (54.17%) showed the highest frequency in loam. The distribution of PPNs varied with different altitudes. The diversity of this phenomenon was closely related to host plants. These results could improve understanding of the distribution of PPNs and provide important information for controlling PPNs.